Diseases of the vasculature, such as stenoses, strictures or aneurysms in blood vessels and other body vessels can be treated by the implanting a payload, such as a stent, graft, or the like, at the site of disease. Such payload can be carried to the site of implantation by a delivery device having a catheter for carrying and deploying the payload. The catheters can be expected to carry the payload over a relatively long distance, often from an incision in the patient's groin area, through the vasculature, to a location where action is required. For example, a site in the vicinity of the patient's heart may be the target for payload deployment.
From incision to deployment site, the path is defined by the interior of a vessel that the catheter must travel. The vessel may have segments that are difficult to traverse. Curves or bifurcations in vessels exemplify two particular kinds of segments that can present such difficulties. Likewise, the deployment site may be curved, or a bifurcation may be present at the site of deployment.
A bifurcation in a vessel is a location where the vessel divides into two branches or parts. The vessel bifurcations generally have circumferential asymmetry. That is, bifurcated vessels generally exhibit asymmetry around their circumference at the point where the main vessel divides into one or more branches. Thus, the opening in the side branch vessel where the side branch vessel joins the main branch vessel may be asymmetrical. The side branch vessel may join the main branch vessel at an oblique angle, which may contribute to the asymmetry of the bifurcation cross-section.
One kind of prior art bifurcation delivery device employs multiple guidewires and/or the clinician to orient and manipulate the device relative to the bifurcation. For example, attempts have been made to accomplish this solely through the use of two wires or wire-like elements (one in each branch of bifurcation) to force rotation of the device to match the vessel anatomy. This approach has shortcomings. First, by requiring delivery of the medical device to the location of the bifurcation over two wires (for substantially the entire delivery), the chance of wire wrapping is greatly increased. This prevents complete delivery of the device and can result in the clinician having to withdraw a wire and rewire the vessels, causing significant procedural delay and patient risk. Second, reliance on two wires for device orientation is typically insufficient to guarantee full and proper alignment of the entire medical device with the side branch ostium (particularly the portion of the device proximal to the carina (or apex) of the bifurcation) Even when both branches of the bifurcation are wired and the medical device is seated on the carina, the wires are not able to exert enough rotational influence on the device to align the whole length of the payload.
In any event, carrying the payload through a vessel curvature, a bifurcation, or otherwise deploying the payload at such locations can present challenges in terms of traversing or accessing the site. Furthermore, where the payload needs to be in a specific orientation (such as for maximizing the therapeutic effect or diagnostic purpose of the payload), achieving the desired orientation in such curvature or bifurcation presents yet another challenge to the person of skill in the art.
U.S. Pat. No. 6,544,218, entitled “Catheter With Biased Shaft” is disclosed as a reference of interest.